Help with research please

I wonder if anyone can help a newbie to this site?

I'm researching my uncle's Army records. He was a private in the Army and we were always told that he was killed " in the battle of Arnhem" by a sniper. However, the records and letters from the chaplain and commanding officer at the time suggest he never got to within 100 miles of Arnhem. His war record (which I have just received) came as quite a shock as it appears he trained as a glider pilot. Whether he was killed in that capacity I don't know, but I'm hoping a search of the war diaries might shed a little more light.

In the meantime, I don't really understand the lingo on the records and I hope somebody can. His service appears to have been as follows -
Date of enlistment 8 Jan 1942
8.1.42 Posted to 2/5 Welch Weymouth
8.7.42 Granted W.P.P at xx? Swanage
23.2.43 Adm to Porlivey? E.M.S
16.3.43 Disch Porlivey? E.M.S
13.7.44 RXNMJ. Struck off strength
25.7.44 Posted 1/5 Welch NWE
23.9.44 Killed in action

Other info is that he was awarded a war medal 1939/45 but nothing suggests mentions in despatches etc. He appears to have applied for RAF Volunteer Reserve to be a glider pilot. He was "Boarded" and accepted as suitable for glider pilot training on 13 Jan 1944 and I think may have gone to RAF RTU? for glider pilot training in Jan 1944, name of school ACSB Doncaster? He also appears to have initially spent 3 months in the Home Guard before joining 2/5 Welch. His original sign up paper seems to be with the Territorial Army?

Any help, info, tips or suggestions most welcome. Thanks.

Janet